Tobacco use remains the number one cause of premature morbidity and mortality in the United States. Despite comparable rates of smoking, young adults are less successful at quitting and use cessation treatment less often than smokers of other ages. Studies of Internet-based smoking cessation interventions have poor retention rates with young adult smokers, and websites for young adult smokers have primarily targeted the college student population. Social media, integrated into the lives of many young adults, represents a promising strategy to deliver evidence-based smoking cessation treatment to a large, diverse audience of young adult smokers. However, little is known about how to maximally utilize social media to engage young adults in an empirically-based intervention for smoking cessation. The overall goal of this proposal is to support the candidate's development of skills to perform smoking cessation intervention research with young adults using online social media. The career plan includes training in the conduct of clinical trials, use of social media for health behavior change, ethical issues in online research, tobacco policy and marketing to young people, and leadership in psychiatry and outcomes research. The UCSF Department of Psychiatry and the NIDA-funded San Francisco Treatment Research Center (P50 DA009253) provide an exceptional research environment. The primary mentor holds expertise in treatment of tobacco dependence in special populations including use of computer-delivered interventions with young adults. The advisory team brings further expertise in research and treatment ethical issues, online interventions, and tobacco control research, media, and policy. The overall goal of the proposed research is to develop and test in a randomized clinical trial the efficacy of a stage-based smoking cessation intervention for young adults age 18 to 25 to be delivered online using Facebook. The specific aims are to: 1) Design and test the feasibility (N = 48) of a motivationally tailored Facebook- based smoking cessation intervention for young adults and; 2) Evaluate the efficacy of the intervention in a randomized trial (N = 480). It is hypothesized that the intervention will successfully engage young adult smokers and that social media is a feasible delivery mechanism for smoking cessation treatment. Further, the intervention is hypothesized to be more effective than a control condition (referral to a national smoking cessation website) in producing biochemically verified abstinence from cigarettes, increased commitment to abstinence, and greater likelihood of making a quit attempt at 3, 6, and 12 months follow up. Given the complex risk behavior profiles of young adult smokers, and the potential to leverage social media interventions to address additional risks, a secondary aim will examine the frequency and correlates of other health risk behaviors in our study sample, including alcohol and illicit drug use; poor sleep quality, sedentary behavior, unhealthy diet, depression, and high-risk sexual behavior. Results will inform the extension of the intervention to address health risk behaviors in addition to tobacco during the next stage of the applicant's career.